Instantaneous starting electric lamp



Aug. 1, 1950 Filed March 2, 1948 M. E. MACKSOUD INSTANTANEOUS STARTINGELECTRIC LAMP 3 Sheets-Sheet 3 INVENTOR.

, jmaw Patented Aug. 1, 1950 UNITED STATES PATENT OFFICE INSTANTANEOUSSTARTING ELECTRIC LAMP Michel E. Macksoud, Newburyport, Mass, assignerto. Cooper-Hewitt Electric. Company, Ho-

boken, N. J.

Application March 2,1948, Serial No. 12,655

3 Claims. (01. 315-336) desired spectrum characteristics, butparticularly it includes a means for instantly initiating the strikingof the arc discharge in the mercury tube, thereby materially improvingthe eificiency of the sun lamp.

Another object of this invention is to further increase the efficiencyof a sun lamp by the redesign of the arc discharge tube, which includesreplacing the conventional starting coil usually mounted therein withone or more ionizing probe type electrodes. This construction permitsthe elimination of the conventional thermostatic switch assembly withits inherent mechanical'deficiencies, and as well the usual time delayfactors involved for initiating the striking of an arc in the mercurytube just prior to its complete operation. This time delay, caused bythe opening of the thermostatic switclrbreaking the electrical circuitto the starting coil, produces a flicker in the initiai. operation ofthe conventional lamp, which by the use of my inventionis elimi nated.

Another object of this invention is to increase the efficiency of a sunlamp assembly by utilizing a type of mercury vapor tube, having a pairof sharply pointed ionizing probe electrodes at each end of the arcdischarge tube to facilitate striking an are at considerably lowerpotentials than the line potentials available from house current supply.

A further object of this invention is to make use of a probe type aredischarge tube, having pointed ionizing probe electrodes at both ends ofthe arc, discharge tube, in order to facilitate the operation of the sunlamp on either alternating or direct current at the usualvoltagesobtainable therefrom.

Another further object of this invention is to construct the probeelectrodes in such a manner as to facilitate ionization of thegascontent of the arc discharge tube at lower potentials than may bepossible otherwise, by increasing the potential field established at thepointed ends of the probe electrodes.

These, and other features of this invention, will be best understood andappreciated from the described form and the two preferred embodimentsthereof, selected for purposes of illustration and shown in theaccompanying drawings, in which? Fig. 1 is a view of elevation ofa'complete sun.

lamp portion of the bulb being shown as broken away to more clearlyillustrate the position of" the component elements of the mountassembly.

Fig.2 is a view in elevation of another embodi- I ment of the sun lamp;portions of the bulbbeing shown as broken away to more clearlyillustrate the use of the arc discharge tube having probe ionizingelectrodes at each end of the arc tube;

Fig. 3 is a circuit diagram of the lamp mount assembly of Fig. I.

Fig. 4 is a circuit diagram of assembly of Fig. 2.

The sun lamp of Fig. l is shown as comprising Q a glass bulb I havingtransmission characteristics particularly efficient in ultra-violetspectra, tgsaid bulb ii preferably being etched on the inner surfacethereof, and having a reflecting. surface 5* within the bulb terminatingin. the cut-off line I, sothat the open face 9 of the bulb permits theracliations of ultra-violet and infra-red topenetrate therefrom upon anexposedobject. The-lamp bulb I cemented to an electric lamp base 3having terminal connections 5! and 53. mount assembly sealed within thebulb l comprises glass stem ll, supporting lead wires 13 and i 5 and amercuryarc diseharge'tubeE l-incandescent baliast filament l3 and 44interconnected in. series together with the arc discharge tube 21"- andmounted in parallel adjacency thereto, and.

between the metalliesupporting platforms t1 and Z-i insulated; by theinsulators and ailixed in position by. eyelets 25. The are dischargetube 2! comprises electrodes M at each end. of the arc discharge. tubeand the probe ionizing electrode 36 having, a sharp point 3! on the endthereof, the probe electrode. being connected through its lead wire tothe resistor 33 by means of con-- nection. 39, the other side of theresistor being The electrodes 280i the are discharge tube 21 areconnected in. series. with the ballast filaments. 43. and by welded. tothe. support lead [3.

meansoffiexible lead connections 38 and 49.;

Fig. 2 shows essentially the same component elements of the sun lamp ofFig. 1, the-principal difference bein the. structural features ofthe.arctube 2.1 ,having electrodes 28, and-spacedadthe lamp mount The sunlamp jacently to each of the oppositely disposed electrodes 28 are theionizing probe electrodes 30 having sharp points on the ends thereofshown as 3|, each of said ionizing probe electrodes being connected inseries with high resistances 33 and 36 through connections so as toestablish a maximum potential difference between the ends of the probes30 and points 3| and the are discharge tube electrodes 28 when electriccurrent usually obtained from house current supply is applied thereto.

Fig. 3 illustrates a circuit diagram of the lamp mount assemblycomponents of Fig. 1, which includes the arc discharge tube 21 and theseries connected ballast filament 43 and 44 endin in the terminals ofthe lamp and 53. The ionizing probe electrode 30 is connected throughflexible lead 39 to the resistor 33 and to the lead thereby establishinga potential charge at the terminus of the probe shown as the sharpenedpoint 3i so that a potential differ" ence of sufficient value isestablished between the end of the probe electrode 35 and the adjacentmain arc discharge electrode 28, so as to ionize the gas content of thetube 21. When alternating current is applied to the terminals of thelamp El and 53, on one half cycle, the potentials of this current sourceis instantly established at the terminal of the probe electrode 30 shownas the point 3i and adjacent electrode 28, the potentials established atthese two electrodes being momentarily equal to the full line voltageminus the cold resistance values of the ballast filament 43 and 44 andthe resistance 33. Ionization of the inert gas content (argon) occurs inthe area of electrode 28 and. adjacent probe electrode 33. This servesinstantly, not only to ionize the gas content of the tube, but also toheat the adjacent electrode 28 to some degree of electron emission so asto initiate an arc discharge between the electrodes 28. This functiontakes place in an extremely short period of time so that the effect oftime delay between the function of ionization and subsequent arcing ofthe tube is unnoticeable. The resistor 33 being of considerably highresistance value and in excess'value to the resist-.

probe electrodes 30 and their respective adjacent electrodes 28.

In this type of sun lamp, the ionization of the inert gas content ateach end of the tube facilitates a more uniform and instantaneous arc tobe initiated particularly at lower applied potentials. This type of arcdischarge tube when correctly designed in accordance with thedisclosures of my invention, is readily applicable to be operated inconjunction with either alternating or direct current. In the case ofdirect current operation, one electrode serves as a cathode and theother oppositely disposed electrode serves as the anode of the arcdischarge tube dependent upon the polarity of the direct current sourceof supply when applied to the lamp.

ance or voltage drop of the arc discharge in merely serves to preventarcing between the" probe electrode 30 and the adjacent arc dischargeelectrode 28. Although the major arc discharge occurs between theelectrodes 28, a minute current flows through the probe electrode 3!!and the resistor 33. This, however, does not detract from the efficiencyof the lamp, as the current value is insignificant, the amount of suchcurrent being dependent upon the resistance value of the resistor 33,and the geometric design and spacing of the respectively adjacent probeand arc discharge electrodes.

Fig. 4 is a circuit diagram of the mount assembly components of the sunlamp of Fig. 2. The only major difference lies in the arc discharge tube21, which is shown as having probe 36 and are each connected separatelyto the oppositely disposed probes so so as to etablish a maximumpotential difference between the e This particular sun lamp assemblyincluding a probe type are tube, eliminates the need for a thermostaticswitch for starting the operation of the lamp. The important feature ofthis type of arc tube construction resides in the probe electrodedesign. In place of a starting coil filament, a probe electrode isutilized. In function, the probe merely cooperates to ionize the inertgas in the area in which it and the adjacent main electrode of the arctube are placed. The ionization of the inert gas is sufllcient toinitiate an arc discharge between the two main electrodes of the tube.The action is simultaneous, and appears to be instantaneous. The probemay be designed to have a sharpened point at its extreme end in order toincrease the potential field at this point, and hence reduce theionization potentials required. With a given applied voltage, the chargeper square centimeter at the end of the probe will be much greater withthe case of a sharp pointed probe than in the case of a probe that isnot pointed. The per cent of change in the diameter of the wire to apoint determines the effective increase in the charge. By charge ismeant the quantity of electrical energ (quantity of electricity) ormeasure of displaced electrons. The probe is connected in series with ahigh resistance of a value higher than the resistance of the ballastfilament, and the opposite end of this resistance is connected to theopposite side of the line so as to establish a potential differencebetween the probe electrode and the adjacent main electrode of the arctube. More than one probe electrode may be utilized to effect ionizationand to initiate the arc, although one probe electrode has been found tobe quite sumcient. The series resistor for the probe is intended merelyto limit the current flowing in the ionized path and to, thereby,prevent arcing between the probe and the adjacently disposed mainelectrode.

Referring to Fig. 3, in describing the operation of the sun lamp of Fig.1, when alternating current of 50-60 cycles and having a potential of-130 volts, such as commercially supplied for home lighting, is appliedto the terminals 5| and 53 of the sun lamp, on one half cycle, themaximum potential difference of the applied line voltage is instantlyestablished upon the probe electrode 36 from terminal 51, through theresistance 33 and lead connector 39, as well as at adjacently disposedarc tube electrode 28 from terminal 5|, through lead I 3, ballastfilament section 43, support hook 45, support platform 2!, support hook45, ballast filament section 44, and connector 38. The potentials thusestablished at electrode 28 and adjacent probe electrode 30 areequivalent to the maximum line potentials minus the voltage dropeffected by the cold resistances of ballast filament sections 43 and 44and the resistance of probe resistor 33. However, the potential at thepointed end 3| of probe 30 may be of a correspondingly higher potentialdue to the electrical characteristics of this pointed probe electrode aspreviously described.

The potential difference thus established at electrode 28 and adjacentprobe electrode 30 is sufficient to cause ionization of the inert gascontent of the arc tube 21. Oppositely disposed electrodes 28 of the arcdischarge tube 27 are coated in the manner described in my copendingapplication entitled "Process for Coating and Activating Gaseous ArcDischarge Electrodes. These electrodes are highly electron emissive atrelatively low operating temperatures, and have characteristics similarto cold cathodes. The ionization of the inert gas of the tube 21particularly in the area of electrodes 28 and 30,0auses some degree ofheating of the electrode 28 and the consequent electron emissionproduced thereby facilitates the striking of an are between the mainelectrodes 28 of the arc tube. The ionization of the gas content of thetube by this function of the probe electrode, also serves to vaporize asmall quantity of the mercury deposit Hg in the arc tube 21, whichincreases the conductivity of the gaseous column within the arc tube.The mercury vapor and metallic deposit shown at 25 in the arc tube isonly initially deposited thereon, but subsequently revaporizes andenters the are stream, as is also described in my copending applicationmentioned previously.

Referring to Fig. 4, in describing the operation of the sun lamp of Fig.2, the function of the separate probe electrodes oppositely disposed andshown as 30 and 30, and each adjacent the main arc tube electrodes 28and 28, cause ionization of the inert gas content at each end of the arctube 21. This permits lower applied potentials to be used in order toinsure starting of the arc discharge of the arc tube 21. This may befound to be desirable where the potentials of the supplied house currentare of a lower value than standard potentials, or where these valuesdrop to lower levels during periods of high loads. Separate resistors 33and 36 are used to limit the current density in each respective probeelectrode 28 and 28. This particular type of dual probe electrodeconstruction incorporated in the arc tube 27 also facilitates operationon direct current, whereby it is immaterial whether the polarity of thecurrent is applied in one direction or the opposite, since each of theoppositely disposed arc tube electrodes can function as an anode or as acathode. On direct current operation, the use of a fixed condenser,which may be mounted within the base of the sun lamp and connectedacross its terminals 5| and 53, or across the terminals of the resistor33 to the probe 30 and the adjacent main electrode 28, was found tofacilitate the initial striking or firing of the arc, due to thecharging and discharging effect produced by the condenser when directcurrent potentials were applied thereto.

The probe electrodes may also be coated to increase their electronemissivity, although they have been used successfully without anyelectron emissive coatings.

Having thus disclosed my invention and described two embodimentsthereof, but Without intending to limit it to the construction as shown,I claim and desire to secure by Letters Patent:

1. An electric lamp comprising a mercury vapcr are discharge tube, apair of arc discharge electrodes mounted in said tube in spacedrelation, a sharply pointed probe electrode disposed in said tubeadjacent each of said are discharge electrodes, an incandescent ballastfilament connected in series with one of said are discharge electrodes,and a pair of resistors each connected at one end to one of said probeelectrodes and at its other end to the opposite arc discharge elecrode,whereby a substantial part of the potential difference between said arcdischarge electrodes is also established between each pointed probeelectrode and the adjacent arc discharge electrode.

2. An electric lamp comprising an arc discharge tube, a pair of arcdischarge electrodes mounted within said tube in spaced relation, asharply pointed probe electrode mounted in said tube closely adjacentthe first of said arc discharge electrodes, a ballast filament connectedin series with the first of said are discharge electrodes, and aresistor connected at one end to said probe electrode and at the otherend to the second of said are discharge electrodes.

3. An electric lamp comprising an are discharge tube, a pair of arcdischarge electrodes mounted within said tube in spaced relation, asharply pointed probe electrode mounted in said tube closely adjacentthe first of said are discharge electrodes, a ballast filament connectedin series with one of said are discharge electrodes, and a resistorconnected at one end to said probe electrode and at the other end to thesecond of said are discharge electrodes.

MICHEL E. MACKSOUD.

REFERENCES @I'EED The following references are file of this patent:

UNITED STATES PATENTS of record in the

